Re-register in production mode using saved credentials
In production mode, after reading registration credentials, imlightsw should ping the monitor. The ping should get a response saying the registration is valid.
If the registration is not valid then the registration should be cleared and we go into standby mode forcing the user to re-register the device. This is how you deal with devices whose registration have been cleared from the monitor but the device doesn't know it (perhaps it was powered off when the device was cleared from the monitor).
A blink pattern needs to be displayed if we have to re-register. Use BP_NOT_REGISTERED.
This will require a new API for the monitor: POST /ping which accepts the encrypted "ping" message. If decrypting the ping fails then the response is 401, otherwise it's 200.